PD178016GC-051_15 Datasheet, PDF (48/96 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCONTROLLER WITH BUILT-IN PRESCALER, PLL FREQUENCY SYNTHESIZER, AND IF COUNTER FOR AUTOMOTIVE FM/MW/LW RADIO APPLICATIONS

µPD178016GC-051
(5) Identification of priority of METHOD
(a) Identification of method
METHOD A is identified if the AF code in that portion for the AF list where the number of stations and AF
codes are paired is the same three times in a row. METHOD B is identified if this AF code differs even once.
This identification is made each time the tunable frequency has been changed.
(b) Setting of priority by METHOD
Each of the recorded AF codes is assigned a priority. The procedure for updating or searching the AF list
is determined according to the priority.
The AF code is read with priority 5 until METHOD is identified.
All the AF codes are read with priority 2 with METHOD A.
METHOD B is set as follows:
Number of stations AF1
AF1
AF2
AF1, AF2, TF condition
AF1 = TF
AF1 < AF2
AF1 ≠ TF
AF1 = TF
AF1 > AF2
AF1 ≠ TF
Priority
2
3
4
5
Priority
High
Low
Priority 1 is set to the frequency at which a station is actually received.
(c) Updating AF list
• Processing when AF code to be read is not in RDS memory
An AF code is added to the beginning of the priority that is the same as that of the AF code to be read.
If, as a result, the RDS memory capacity exceeds the rated value, the AF code having the lowest priority
is deleted.
• Processing when the AF code to be read is already in RDS memory
If the priority of a previously read AF code is higher than that of the AF code to be read, the AF code is
not read.
If the priority of the AF code to be read is higher than that of a previously read AF code, the previously
read AF code is deleted and a new code is added.
3.1.6 Best station
The reception state is checked when an RDS station is received. If the reception is poor, a search is made for
a station having the same PI code, and the frequency is changed. This operation is performed in RDS mode.
(1) Best station start condition
If the reception of the newly received frequency remains poor even after the following operations have been
performed, best station is started (when signal meter reading < SMT_B/C input voltage: +0.3125 V).
However, best station is not started when the FM tuner is turned on.
If a station for which the reception is good cannot be found as a result of best station, PI seek is started.
• Radio mode selection
• Band switching
• Preset memory calling
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